Castle Mound was originally a late 11th century earthwork motte and bailey fortress, founded by the de Montbegon family. The conical motte is slightly oval but sadly landscaping has truncated the top and considerably altered the base of the motte. The position of the bailey has been lost but a platform to the west, which now supports the church of St Wilfrid's, probably defines its site. A mile north-east is Thurland Castle and 2 miles south-west is Hornby Castle.